Solar radiation absorbing panel

ABSTRACT

An invention proposes a solar radiation absorbing panel that serves preferably for air heating, 
     The solar radiation absorbing panel is constructed from two metal sheets. 
     The metal sheets are sealingly joined along their edges. 
     The metal sheets are provided with mechanical or magnetic means; the both metal sheets are interlocked by these means along some lines or at some spots. 
     This ensures diminishment of buckling these sheets under operating pressure and establishing of a certain distance between them with small deviations with respect to its average value. 
     The outer side of one metal sheet is coated with a black or selective paint absorbing solar radiation.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable

BACKGROUND OF THE INVENTION

Usage of flat plate solar collectors for immediate air heating presents attractive solution for many applications: heating of dwellings; air conditioning systems, which operate with usage of liquid or solid desiccants; drying processes in industry and agriculture.

These flat plate solar collectors can operate with low overpressure with respect to the ambient atmospheric pressure.

It allows in turn constructing solar radiation an absorbing panel for these solar collectors as two metal sheets, which are positioned for the most part in parallel at a distance of few millimeters and sealingly mutually joined along their edges. Two terminal sections of one metal sheet are provided with openings, which are, in turn, in fluid communication with headers provided with inlet and outlet connections. In such a way, the internal space formed between the metal sheets and serving as a duct is in fluid communication with these inlet and outlet connections.

The external side of the upper sheet is coated with black or selective paints absorbing solar radiation.

These solar selective coatings are described, for example, in article: McDonald, G. E: “Spectral reflective properties of Black Chrome for use as a Solar Selective Coating”, Solar Energy Journal 17, 119 (1975).

The solar radiation absorbing panel can be installed into a box with glazing its upper aperture and a thermal insulation of the box's bottom.

Such solar radiation absorbing panel and its operation is described in the book: Frank Kreith and Jan Kreider PRINCIPLES OF SOLAR ENGINEERING, Hemispher Publishing Corporation, 1978, p. 231 and p. 446.

However, this simple design of the solar radiation absorbing panel requires application of metal sheets with high rigidity in order to solve a problem of significant buckling of the metal sheets under internal operating pressure in the duct formed between these metal sheets.

This buckling causes, in turn, diminishment of heat transfer coefficient for heat transfer from the air to the metal sheet absorbing solar radiation, and, as a result, it diminishes efficiency of the solar radiation absorbing panel.

There are some US patents intended to solve this problem.

U.S. Pat. No. 3,943,911 describes a solar heat exchanger, which comprises: A. a base and an extended surface thereon for facing frontward toward the sun, B. means communicating with said surface to conduct liquid to flow in dispersed condition adjacent said surface, and C. a sheet overlying said surface and spaced therefrom sufficiently closely to cooperate therewith for filming the flowing liquid, said sheet adapted to receive solar radiation for promoting heat transfer to the filmed and flowing liquid.

U.S. Pat. No. 4,010,733 discloses a solar energy collector unit comprising: an expanded metal energy collector panel including an upper sheet and a lower sheet; a seam weld connecting said upper and lower sheets and defining a rectangular energy collecting area; a plurality of spaced spot welds within said rectangular energy collecting area, defining a plurality of fluid flow channels; fluid inflow means at one end of said rectangular energy collecting area, and fluid overflow means at the opposite end of said rectangular energy collecting area (Claim 7).

U.S. Pat. No. 4,062,350 describes a solar water heating panel having a base sheet and a metallic absorber sheet affixed in close parallel relationship to one another. The water passes between the two sheets and is heated by solar heat transfer through the absorber sheet into the water.

The spacing between the absorber sheet and the base sheet may be controlled by spacers which may be held externally or internally to the heater. For instance, a plurality of dimples may be formed in the absorber sheet and with the use of a metal base sheet the absorber sheet may be welded at each of these dimples to the base sheet. Likewise, the dimples may be located in the base sheet instead of the absorber sheet. Alternatively, a rubber or other corrosion resistant and flexible member may be placed between the absorber sheet and the base sheet at a plurality of locations and a rivet, nut and bolt or other fastening means passed through the assembly and tightened to prevent the leakage of water around the fastener. Still further, a plurality of polymeric or other corrosion resistant spacers may be adhered to the inner surfaces of the absorber sheet and base sheet to hold the two sheets in a spaced apart parallel relationship.

It should be noted that U.S. Pat. No. 1,250,260 describes application of rivets as spacers for two parallel metal sheets of a solar radiation absorbing panel.

U.S. Pat. No. 4,327,707 describes a flat plate collector that employs high performance thin films. In the preferred form, the apparatus features a substantially rigid planar frame. A thin film window is bonded to one planar side of the frame. An absorber of laminate construction is comprised of two thin film layers that are sealed perimetrically. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. Absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

The films comprising the absorber are further bonded together at a plurality of locations across their surface so as to maintain a high degree of parallelism between said films as said heat transfer fluid flows through the envelope, thereby assuring that a substantial portion of the surface of the films is wetted (Claim 3).

However, this patent does not disclose means for such bonding “at the plurality of locations”.

U.S. Pat. No. 4,396,007 discloses a solar heat exchanger having a mesh sandwiched between two thin films for transfer of radiant solar energy to a fluid drawn through the mesh by suction.

U.S. Pat. No. 4,474,172 discloses a solar water heating panel and method of constructing such a solar panel from a pair of thin sheets bonded together around their peripheral edges and having at least one of the sheets formed with resiliently flexible areas defined by a plurality of abutting concave hexagonal areas or zones. The center of each hexagonal zone is formed as a dimple, concave with respect to the opposite sheet, whose radius of curvature is greater than the radius of an inscribed circle within said zone. The abutting zones between each hexagonal zone are formed convex relative to the opposite sheet and have a radius less than that of an inscribed circle. In a preferred form, the sheets are joined together at the center of alternate spaced-apart hexagonal areas. In this way, except for the centers bonded near the panel edges, each joined hexagonal center is surrounded by six unjoined areas to form both transverse and longitudinal flow passages through the panel.

U.S. Pat. No. 8,985,097 describes a device and method of its production for a micro-channel thermal absorber to be used as a solar thermal collector, heat collector, or heat dissipater, extruded or continuously cast in one piece or in modular segments from a metal, plastic, or glass and assembled into panels of different structures seamlessly integrated into the envelope of a building as covering layers or structural elements. The micro-channel thermal absorber comprises an active plate, a back plate adjacent to the active plate, and a plurality of micro-channel walls arranged substantially perpendicular to the active plate and the back plate to define a plurality of fluid transport micro-channels configured to allow fluid flow there-along, wherein the micro-channel walls constitute supporting elements between the active plate and the back plate to provide structure.

U.S. Pat. No. 9,267,710 discloses solar thermal collectors, solar heating systems, and thin plate heat exchangers and absorbers. The thin plate heat exchangers and absorbers may be used for solar applications and/or non-solar applications. In an exemplary embodiment, a solar thermal collector generally includes a first layer comprising polymer and configured to allow sunlight to pass therethrough. A second layer comprises polymer and is configured to absorb thermal energy from sunlight. The second layer includes edges heat sealed to edges of the first layer. A permeable core is disposed between the first and second layers. In operation, a heat transfer fluid may flow through the permeable core and directly contact the second layer, whereby thermal energy is transferrable from the permeable core and the second layer to the heat transfer fluid.

In addition, there are U.S. Pat. Nos. 4,140,103, 4,205,658, 4,205,662, 4,211,213, 42,865,823, 4,292,955, 4,455,999, 4,473,066, 6,526,965 and 9,127,860, which solve the problem of buckling by application of corrugated sheets or application of sheets provided with sets of ribs.

It causes, in turn, a complicated problem of fluid communication between ducts formed by such corrugated sheets with headers arranged at the terminal sections of the duct and makes these solar radiation absorbing panels very expensive.

On the other hand, these patents do not allow to apply plates from cheap thin tin or galvanized steel plates for manufacturing of solar radiation absorbing panels, which can be used in construction of solar collectors.

BRIEF SUMMARY OF THE INVENTION

An invention proposes a solar radiation absorbing panel that serves preferably for air heating. However, the proposed solar radiation absorbing panel can serve for water heating.

The solar radiation absorbing panel is constructed from two metal sheets.

One of these metal sheets is provided with two sets of openings at its opposite terminal sections. The opposite terminal sections are joined sealingly with two headers provided with inlet and outlet connections. In the case of application of the solar radiation absorbing panel for air heating, it is possible to substitute the header with its inlet connection by a fan installed immediately on the metal sheet in such a manner that the aperture of the fan overlaps completely the openings serving for ingress of the air.

The metal sheets are sealingly mutually joined along their edges by soldering or roll seaming.

The distance between the metal sheets is ensured by pairs of profiles, which are arranged on the inner sides of the metal sheets longitudinally or transversely to direction of fluid motion in the duct formed between these sheets; these profiles are fastened on the metal sheets by soldering or gluing and the opposite profiles of each pair of the profiles are brought in their interlocking; it diminishes significantly buckling of the metal sheets under operating pressure of the fluid.

There are several versions of different profiles, which provide interlocking of the opposite metal sheets along lines or in some spots.

In a first embodiment the both profiles in one interlocking pair are V-shaped profiles.

After placement of two sheets in parallel at closest distance, when the parallel profiles are turned inward, the sheets are shifted in parallel with following interlocking the V-shaped profiles of each pair.

In a similar technical solution, the both metal sheets are provided with louvers protruding inward the space between these metal sheets and the openings of these louvers are closed sealingly from the outsides by metal strips by soldering or gluing.

In another version, the both profiles of one pair of the profiles to be interlocked are U-shaped.

In an additional version, the both profiles are Z-shaped profiles (Zee beams) with webs, which are situated perpendicularly to their lower and upper shelves.

In the case, when the profiles described above are oriented transversely to direction of fluid flow in the duct between the metal sheets, the protruded shelves of the profiles are toothed and placed in such a manner on the metal sheets, that in the shifted state and their interlocking, their teeth are mutually overlapped and do not prevent fluid motion via these protruded shelves. Analogically, the protruded shelves of each pair of the profiles described above can be provided with perforations.

There are two additional versions of pairs of profiles fastened on the opposite metal sheets longitudinally or transversally to direction of fluid (gas or liquid) flowing in the duct formed between these metal sheets. One profile of a pair, which is intended to be interlocked, is an angle section with its protruded shelf provided with longitudinal rectangular perforations and the second one is an angle section with a blunt angle between its shelves, wherein the protruded shelf is toothed.

In such a way, in the state of interlocking of the profiles of one pair, the teeth of the protruded shelf of the second profile are introduced into the rectangular perforations of the first profile.

In this case, the angle section with the rectangular perforations may be substituted by a corrugated strip with rectangular corrugations.

It should be noted that it is possible to apply some other combinations of the profiles described above as pairs with ability of their interlocking.

In another version, there are two metal sheets from a ferromagnetic metal; one of these metal sheets is provided with cylindrical dimples, which are protruded outwards relatively to the internal duct formed between the metal sheets.

Cylindrical permanent magnets are disposed in the cylindrical dimples and partly protrude from them (the height of these cylindrical permanent magnets is larger than the depth of the cylindrical dimples, and their edges, which are inserted into the cylindrical dimples, are chamfered).

In such a way, these cylindrical permanent magnets attract the opposite ferromagnetic metal sheet ensuring diminishment of buckling these metal sheets under operating pressure and provide small deviations regarding a certain average distance between them.

In an additional version, the cylindrical dimples of one ferromagnetic sheet are turned inward the internal duct between the two ferromagnetic sheets and the ring permanent magnets are placed around of these cylindrical dimples. The internal edges of the ring permanent magnets facing the metal sheet, which is provided with the dimples, are preferably chamfered. The dimples may be shaped in this case as spherical dimples.

These ring permanent magnets are protruding regarding the bottoms of the cylindrical dimples and they attract the opposite ferromagnetic metal sheet.

In the third version of application of permanent magnets for interlocking of two opposite ferromagnetic sheets, there is a frame with a set of parallel metal strips installed in it; the metal strips are fabricated from a spring metal and each metal strip is provided with some omega-shaped sections of the same orientation.

We determine a diameter of the omega-shaped section as the diameter of a maximum circle, which can be inscribed into the planar cross-section of the omega-shaped section in such a way that the center of this circle is found on the same side as the omega-shaped section itself relatively to the embouchure of the omega-shaped section.

The cylindrical permanent magnets have diameter somewhat higher than the diameter of the omega-sections; in such a way these cylindrical permanent magnets are installed in the omega-sections and held in them by forces of elastic deformation of these omega-sections.

At the same time the height of the cylindrical permanent magnets is larger than the width of the strips (the strips are installed in the frame in such a manner than their planes are perpendicular to the frame's plane).

In this case, the frame with these strips and with the cylindrical permanent magnets is placed between two metal ferromagnetic sheets with following fabrication of the solar radiation absorbing panel as it was described above; i.e., sealingly joining of the both metal ferromagnetic sheets along their edges, when one of the metal ferromagnetic sheet is provided with openings at its opposite terminal sections, and following installations of headers provided with inlet and outlet connections.

In such a way, the cylindrical or ring permanent magnets serve in these versions as spacers and, on the other hand, they diminish the buckling phenomena for the metal ferromagnetic sheets under operation pressure.

The outer side of one metal sheet is coated with a black or solar selective paint absorbing solar radiation.

In order to diminish buckling of the solar radiation absorbing panel as the result of the temperature difference between the upper and lower metal sheets, their internal sides may be coated with a black paint with high emission/absorption ability in the infrared range of the electromagnetic spectrum.

There are hook-and-loop fasteners “Velcro”, which reminds some technical solutions proposed in this invention. In addition, there are 3M Dual Lock™ fasteners.

However, the proposed pairs of profiles or permanent magnets in combination with dimples have substantial rigidity and interlocking of these profiles or permanent magnets with both opposite metal sheets is ensured additionally by joining the metal sheets along their edges; this prevents possibility of disengagement of these metal sheets.

Such solar radiation absorbing panels can be used in flat plate solar collectors with or without glazing. In addition, such panels may be used for heat dissipation.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 a, FIG. 1b and FIG. 1c demonstrate correspondingly: an isometric view of an angle; one shelf of this angle is toothed and forms a blunt angle with the plane of the other shelf; an isometric view of an angle with rectangular perforations of its protruded shelf (with respect to plane of the metal sheet on which this angle is installed); an isometric view of a corrugated strip with rectangular corrugations.

FIG. 2 a, FIG. 2b and FIG. 2c demonstrate isometric views of a V-shaped angle, a V-shaped toothed angle and a V-shaped angle with rectangular perforation of its one shelf.

FIG. 2 d, FIG. 2e and FIG. 2f demonstrate isometric views of: an U-shaped profile (FIG. 2d ), an U-shaped profile with rectangular perforations of its upper shelf (FIG. 2e ) and an U-shaped profile (FIG. 2f ), when one shelf of this U-shaped profile is toothed.

FIG. 2 g, FIG. 2h and FIG. 2i demonstrate: a Z-shaped profile (Zee beam) with a web, which is situated perpendicularly to its lower and upper shelves (FIG. 2g ); a Z-shaped profile (Zee beam), when its web and the upper shelf has rectangular perforations (FIG. 2h ); a toothed strip with the L-shaped teeth (FIG. 2i ).

FIG. 3a and FIG. 3b demonstrate the internal sides of the metal sheets with V-shaped toothed angles installed transversely to flow direction in a duct to be constructed from these metal sheets.

FIG. 3c and FIG. 3d demonstrate the internal side of the metal sheets with V-shaped angles installed longitudinally to flow direction in a duct, which is to be constructed from these metal sheets.

FIG. 3e and FIG. 3f demonstrate: the internal side of the lower metal sheet, which provided with louvers fabricated by slitting (FIG. 3e ) and the transverse cross-section A-A (FIG. 3f ) of this lower metal sheet, when the openings of these louvers are sealingly closed by metal strips.

FIG. 3g and FIG. 3h demonstrate: the internal side of the upper metal sheet, which provided with louvers fabricated by slitting (FIG. 3g ) and the transverse cross-section B-B (FIG. 3h ) of this lower metal sheet, when the openings of these louvers are sealingly closed by metal strips.

FIG. 4 is an underside view of the assembled solar radiation absorbing panel.

FIG. 5a and FIG. 5b show transverse cross-sections of two opposite metal sheets with sets of V-shaped angles installed on their internal sides; these V-shaped angles are shown before and after their interlocking.

FIG. 5c and FIG. 5d show transverse cross-sections of two opposite metal sheets; one metal sheet is provided with a set of profiled toothed strips; their teeth form blunt angle with the strip plane just as it is shown in FIG. 1 a; a set of the perforated angles just as it shown in FIG. 1b is installed on the other metal sheet; these metal sheets with their toothed strips and perforated angles are shown before and after their interlocking.

FIG. 5e and FIG. 5f show transverse cross-sections of two opposite metal sheets with two sets of Z-shaped profiles (Zee beams) just as it is shown in FIG. 2 g; these Z-shaped profiles are installed on both metal sheets with opposite direction of their lower and upper shelves; these Z-shaped profiles are shown before and after interlocking of their pairs.

FIG. 5g and FIG. 5h show transverse cross-sections of two opposite metal sheets; a set of profiled toothed strips just as it is shown in FIG. 1a is installed on one metal sheet, and a set of corrugated strips just as it shown in FIG. 1c is installed on the other metal sheet; these profiled toothed strips and corrugated strips are shown before and after their interlocking.

FIG. 5i and FIG. 5j show transverse cross-sections of two opposite metal sheets with two sets of U-profiled strips just as it is shown in FIG. 2 g; these U-profiled strips are installed on both metal sheets with opposite direction of their longitudinal shelves; these U-profiled strips are shown before and after their interlocking.

FIG. 6 demonstrates a transverse cross-section A-A (FIG. 4) of an assembled solar radiation absorbing panel, when the V-shaped angles are installed longitudinally to direction of a medium flow.

FIG. 7 a, FIG. 7 b, FIG. 7c and FIG. 7d demonstrate cross-sections and views from above of two opposite metal sheets, which serve for constructing a duct of a solar radiation absorbing panel; one of these metal sheets is provided with a set of cylindrical dimples.

FIG. 8a and FIG. 8b show longitudinal cross-sections of assembled solar radiation absorbing panels, as it is shown in FIG. 4, with cylindrical (FIG. 8a ) or ring (FIG. 8b ) permanent magnets serving as spacers and for interlocking two metal ferromagnetic sheets.

FIG. 9a shows a planar view of a frame with a set of strips installed in it, when each of the strips is provided with omega-shaped sections.

FIG. 9b and FIG. 9c show the planar view and a cross-section A-A of the frame with the strips and cylindrical permanent magnets fastened in their omega-shaped sections.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a, FIG. 1b and FIG. 1c demonstrate correspondingly: an isometric view of a strip provided with teeth forming a blunt angle with the strip plane; an isometric view an angle with rectangular perforations of its one angle section; an isometric view of a corrugated strip with rectangular corrugations.

FIG. 1a comprises strip 101 and teeth 102 forming the blunt angle with the strip plane.

FIG. 1b comprises an angle section 103, an angle section 104 and rectangular perforations 105.

FIG. 1c comprises a corrugated strip 106 with rectangular corrugations 107.

FIG. 2 a, FIG. 2b and FIG. 2c demonstrate isometric views of a V-shaped angle, a V-shaped toothed angle and a V-shaped angle with rectangular perforation of its one shelf.

FIG. 2a shows the isometric view of the V-shaped angle 200 with an angle shelf 201 and an angle shelf 202.

FIG. 2b shows an isometric view of the V-shaped toothed angle 208 with an angle shelf 203 and teeth 204.

FIG. 2c shows an isometric view of the V-shaped angle 209 with an angle shelf 205, an angle shelf 206 and rectangular perforation 207.

FIG. 2 d, FIG. 2e and FIG. 2f demonstrate isometric views of: an U-shaped profile (FIG. 2d ), an U-shaped profile with rectangular perforations of its upper shelf (FIG. 2e ) and an U-shaped profile (FIG. 2f ), where one shelf of this U-shaped profile is toothed.

FIG. 2d shows U-shaped profile 210, which comprises a lower shelf 211, an upper shelf 212 and web 213.

FIG. 2e shows the U-shaped profile 214, which comprises a lower shelf 215, an upper shelf 216 and rectangular perforations 217.

FIG. 2f shows the U-shaped profile 218, which comprises a lower shelf 219, an upper teeth 220 and webs 221.

FIG. 2 g, FIG. 2h and FIG. 2i demonstrate: a Z-shaped profile (Zee beam) with a web, which is situated perpendicularly to its lower and upper shelves (FIG. 2g ); a Z-shaped profile, when its web and the upper shelf have rectangular perforations (FIG. 2h ); a toothed strip with the L-shaped teeth (FIG. 2i ).

FIG. 2g shows the Z-shaped profile 222 comprising a lower shelf 223, an upper shelf 224 and web 225, which is situated perpendicularly to the lower and upper shelves 223 and 224.

FIG. 2h shows the Z-shaped profile 226 comprising a lower shelf 227, an upper shelf 228, web 229 and perforations 230.

FIG. 2i shows the Z-shaped profile 231 comprising a lower shelf 232 and L-shaped teeth 233.

FIG. 3a and FIG. 3b demonstrate the internal sides of metal sheets 301 and 306 with V-shaped toothed angles installed transversely to flow direction in a duct, which is to be constructed from these metal sheets.

FIG. 3a shows the metal sheet 301, V-shaped toothed angles 302 with teeth 303; these V-shaped toothed angles 302 are installed on the metal sheet 301; openings 304 and 305 are situated at the terminal sections of the metal sheet 301.

FIG. 3b shows the metal sheets 306 and V-shaped toothed angles 307 with teeth 308.

FIG. 3c and FIG. 3d demonstrate the internal side of the metal sheets 309 and 313 with V-shaped angles installed longitudinally to flow direction in a duct to be constructed from these metal sheets.

FIG. 3c shows metal sheet 309 and V-shaped angles 310; these V-shaped angles 310 are installed on the metal sheet 309; openings 311 and 312 are perforated in the terminal sections of the metal sheet 309.

FIG. 3d shows metal sheets 313 and V-shaped angles 314; these V-shaped angles 314 are installed on the metal sheet 313.

FIG. 3e and FIG. 3f demonstrate: the internal side of a lower metal sheet, which provided with louvers fabricated by slitting (FIG. 3e ), and the transverse cross-section A-A (FIG. 3f ) of this lower metal sheet, when the openings of these louvers are sealingly closed by metal strips.

FIG. 3e comprises: a metal sheet 315; openings 316 and 317; louvers 318.

FIG. 3f comprises: the metal sheet 315; louvers 318; strips 319.

FIG. 3g and FIG. 3h demonstrate: the internal side of the upper metal sheet, which provided with louvers fabricated by slitting (FIG. 3g ), and the transverse cross-section B-B (FIG. 3h ) of this lower metal sheet, when the openings of these louvers are sealingly closed by metal strips.

FIG. 3g comprises: a metal sheet 320; louvers 321.

FIG. 3h comprises: the metal sheet 320; louvers 321; strips 322.

FIG. 4 is the underside view of an assembled solar radiation absorbing panel.

It comprises: an upper sheet 401; a lower sheet 402; a soldering seam 403; header 404; openings 405; an inlet connection 406; flange 407; header 408; openings 409; an outlet connection 410; flange 411.

FIG. 5a and FIG. 5b show a transverse cross-section of two opposite metal sheets with sets of V-shaped angles installed on their internal surfaces longitudinally to direction of a medium flow; these V-shaped angles are shown before and after their interlocking.

FIG. 5a and FIG. 5b comprise: an upper metal sheet 501; a lower metal sheet 502; V-shaped angles 503 installed on the upper metal sheet 501; V-shaped angles 504 installed on the lower metal sheet 502.

It should be noted that in the case of application of the V-shaped toothed angles and/or the V-shaped angles with the rectangular perforations, as it was described above, drawings of transverse cross-sections of two opposite metal sheets have similar views.

FIG. 5c and FIG. 5d show a transverse cross-section two opposite metal sheets; one metal sheet is provided with a set of profiled toothed strips; their teeth form blunt angle with the strip plane just as it is shown in FIG. 1 a; a set of the perforated angles just as it shown in FIG. 1b is installed on the other metal sheet; these metal sheets with their profiled strips are shown before and after their interlocking.

FIG. 5c and FIG. 5d comprise: the upper metal sheet 505 with the set of the profiled toothed strips 506 fastened on it; the lower metal sheet 507 with the set of the perforated angles 508 fastened on it.

FIG. 5e and FIG. 5f show transverse cross-section of two opposite metal sheets with two sets of Z-shaped profiles (Zee beams) just as it is shown in FIG. 2 g; these Z-shaped profiles are installed on the both metal sheets with opposite direction of their upper and lower shelves; the Z-shaped profiles are shown before and after their interlocking.

FIG. 5e and FIG. 5f comprise: the upper metal sheet 510 with the set of the Z-shaped profiles 511 fastened on it; the lower metal sheet 512 with the set of Z-shaped profiles 513 fastened on it.

FIG. 5g and FIG. 5h show transverse cross-sections of two opposite metal sheets; a set of profiled toothed strips just as it is shown in FIG. 1a is installed on one metal sheet; a set of corrugated strips just as it shown in FIG. 1c is installed on the other metal sheet; the profiled toothed strips and the corrugated strips are shown before and after their interlocking.

FIG. 5g and FIG. 5h comprise: the upper metal sheet 514 with the set of the profiled toothed strips 515 installed on it; the lower metal sheet 516 with the set of the corrugated strips 517.

FIG. 5i and FIG. 5j show transverse cross-sections of two opposite metal sheets with two sets of U-shaped profiles just as it is shown in FIG. 2 g; these U-shaped profiles are installed on the both metal sheets with opposite directions of their upper and lower sections; these U-shaped profiles are shown before and after their interlocking.

FIG. 5i and FIG. 5j comprise: the upper metal sheet 518 with the set of the U-shaped profiles 519 installed on it; the lower metal sheet 520 with the set of the U-shaped profiles 521 installed on it.

FIG. 6 demonstrates a transverse cross-section A-A (see FIG. 4) of an assembled solar radiation absorbing panel, when the V-shaped angles are installed longitudinally to direction of a medium flow.

FIG. 6 comprises: an upper metal sheet 601; a lower metal sheet 602; flange 603 of the lower metal sheet 602; V-shaped angles 604 installed on the upper metal sheet 601; V-shaped angles 605 installed on the lower metal sheet 602; header 606, its flange 607 and a inlet connection 608; a solar radiation absorbing coating 609.

FIG. 7 a, FIG. 7 b, FIG. 7c and FIG. 7d demonstrate cross-sections and views from above of two opposite metal sheets, which serve for constructing a duct of a solar radiation absorbing panel; one of these metal sheets is provided with a set of cylindrical dimples.

FIG. 7a and FIG. 7b show the cross-section and the view from above of a metal sheet 701.

FIG. 7c and FIG. 7d show the cross-section and the view from above of a metal sheet 702 with cylindrical dimples 703.

FIG. 8a and FIG. 8b show longitudinal cross-sections of two assembled solar radiation absorbing panels, as it is shown in FIG. 4, with cylindrical (FIG. 8a ) or ring (FIG. 8b ) magnets serving as spacers and for interlocking of two metal ferromagnetic sheets.

FIG. 8a comprises: an upper sheet 801 from ferromagnetic metal with its external surface covered by a solar radiation absorbing coating 802; a lower sheet 803 from ferromagnetic metal; this lower sheet is provided with a set of cylindrical dimples 804 directed outwards; a set of cylindrical magnets 805, which are situated in the cylindrical dimples 804 in such a way that the upper sections of the cylindrical magnets 805 are protruded from the plane of the lower sheet 803; header 806 with its flange 807; an inlet connection 808; header 809 with its flange 810; an outlet connection 811; openings 812 and 813 in the terminal sections of the lower sheet 803.

FIG. 8b comprises: an upper sheet 823 from ferromagnetic metal with its external side covered by a solar radiation absorbing coating 824; a lower sheet 814 from ferromagnetic metal; this lower sheet 814 is provided with a set of cylindrical dimples 815 directed inwards; a set of ring magnets 816, which are situated around the cylindrical dimples 815 in such a way that the upper sections of the ring magnets 816 are protruded from the plane of the tops of dimples 815; header 817 with its flange 818; an inlet connection 819; header 820 with its flange 821; an outlet connection 822; openings 825 and 826 in the terminal sections of the lower sheet 814.

FIG. 9a shows a planar view of a frame with a set of strips installed in it, when each of the strips is provided with omega-shaped sections.

It comprises: frame 901; strips 902 with omega-shaped sections 903.

FIG. 9b and FIG. 9c show the planar view and a cross-section A-A of the frame with the strips and cylindrical permanent magnets fastened in their omega-shaped sections.

It comprises: frame 901; strips 902 with omega-shaped sections 903; the cylindrical permanent magnets 904. 

1. A solar radiation absorbing panel comprising: two substantially parallel first and second metal sheets situated at distance of some millimeters relative one another; both said metal sheets are fabricated from ferromagnetic metal; the outer surface of said first metal sheet is covered with a paint absorbing solar radiation; two terminal sections of said second metal sheet are provided with openings; said metal sheets are sealingly joined along their edges; two headers are fastened on the said terminal sections of said second metal sheet; one of said headers is provided with an inlet connection and said other—with an outlet connection; there is a set of cylindrical dimples formed on said second longitudinal sheet; said cylindrical dimples are directed outward the spacing between said first and second metal sheets; permanent cylindrical magnets are placed in said cylindrical dimples; the height of said permanent cylindrical magnets is higher than the depth of said cylindrical dimples.
 2. The solar radiation absorbing panel as claimed in claim 1, wherein the cylindrical dimples of the second metal sheet are directed inward the spacing between the first metal sheet and said second metal sheet, and ring permanent magnets are fastened around said cylindrical dimples; the height of said ring permanent magnets is higher than the depth of said cylindrical dimples.
 3. The solar radiation absorbing panel as claimed in claim 2, wherein the spherical dimples are directed inward the spacing between the first and second metal sheets and ring permanent magnets are fastened around said spherical dimples; the height of said ring permanent magnets is higher than the depth of said spherical dimples.
 4. The solar radiation absorbing panel as claimed in claim 1, wherein there is a frame with a set of parallel metal strips installed in it; said metal strips are fabricated from a spring metal and each said metal strip is provided with some omega-shaped sections of the same direction; the cylindrical permanent magnets with diameter somewhat higher than the diameter of said omega-sections are installed in said omega-sections and held in them by forces of elastic deformation of said omega-sections; said frame with said strips and said permanent magnets is placed between two flat metal ferromagnetic sheets; one of said flat metal ferromagnetic sheets is provided with two sets of openings at its opposite terminal sections; said flat metal ferromagnetic sheets are sealingly joined, provided with headers and the inlet/outlet connections and the paint absorbing solar radiation as it is claimed in claim
 1. 5. The solar radiation absorbing panel as claimed in claim 1, wherein the internal surfaces of the first and second metal ferromagnetic sheets are covered with a black paint.
 6. The solar radiation absorbing panel as claimed in claim 1, wherein the outer surface of the first metal ferromagnetic sheet is covered with a solar selective coating.
 7. The solar radiation absorbing panel as claimed in claim 1, wherein a fan is installed immediately on the back side of the second metal ferromagnetic sheet instead of the header provided with the inlet connection; the aperture of said fan overlaps completely the openings in the terminal section of the metal ferromagnetic sheet related to said header.
 8. A solar radiation absorbing panel comprising: two substantially parallel first and second longitudinal metal sheets situated at a distance of some millimeters relative one another; the outer surface of said first metal sheet is covered with a paint absorbing solar radiation; the terminal sections of said second metal sheet are provided with openings; said longitudinal metal sheets are sealingly joined along their edges; two headers are fastened on the said terminal sections of said second longitudinal metal sheet; one of said headers is provided with an inlet connection and said other—with an outlet connection; parallel opposite profiles are fastened on the internal sides of said first and second metal sheets, said distance of some millimeters relative one another is determined by the heights of said profiles; the pairs of said opposite profiles are interlocked.
 9. The solar radiation absorbing panel as claimed in claim 8, wherein said opposite profiles are V-shaped angles with their pairs oriented oppositely on the first and second metal sheets.
 10. The solar radiation absorbing panel as claimed in claim 9, wherein one longitudinal section of each of the V-shaped angle is perforated or toothed.
 11. The solar radiation absorbing panel as claimed in claim 8, wherein said opposite profiles are Z-shaped profiles (Zee beams) with their pairs oriented oppositely on the first and second metal sheets.
 12. The solar radiation absorbing panel as claimed in claim 11, wherein one longitudinal shelf and/or the web of each of the Z-shaped profiles is perforated or toothed.
 13. The solar radiation absorbing panel as claimed in claim 8, wherein said opposite profiles are U-shaped with their pairs oriented oppositely on the first and second metal sheets.
 14. The solar radiation absorbing panel as claimed in claim 13, wherein one longitudinal section and/or the web of each of the U-shaped profiles is perforated or toothed.
 15. The solar radiation absorbing panel as claimed in claim 8, wherein one profile of a pair intended to be interlocked is shaped as an angle section and its protruded shelf provided with longitudinal rectangular perforations, and the second one is an angle section, which has a blunt angle between its shelves, and its protruded shelf is toothed.
 16. The solar radiation absorbing panel as claimed in claim 8, wherein one profile of the pair intended to be interlocked is a corrugated strip with rectangular corrugations and the second one is an angle section with a blunt angle between its shelves, and its protruded shelf is toothed.
 17. The solar radiation absorbing panel as claimed in claim 8, wherein said opposite profiles are realized as louvers fabricated by slitting in the first and second metal sheets; the openings of said louvers are sealingly closed by metal strips and said louvers are oriented oppositely on said first and second metal sheets.
 18. The solar radiation absorbing panel as claimed in claim 8, wherein the internal surfaces of the first and second metal sheets are covered with a black paint.
 19. The solar radiation absorbing panel as claimed in claim 8, wherein the outer surface of the first metal sheet is covered with a solar selective coating.
 20. The solar radiation absorbing panel as claimed in claim 8, wherein a fan is installed immediately on the back side of the second metal sheet instead of the header provided with the inlet connection; the aperture of said fan overlaps completely the openings in the terminal section of said metal sheet related to said header. 